Genome-Wide Analysis of the Zn(II)(2)Cys(6) Zinc Cluster-Encoding Gene Family in Tolypocladium guangdongense and Its Light-Induced Expression

The Zn(II)(2)Cys(6) zinc cluster gene family is a subclass of zinc-finger proteins, which are transcriptional regulators involved in a wide variety of biological processes in fungi. We performed genome-wide identification and characterization of Zn(II)(2)Cys(6) zinc-cluster gene (C6 zinc gene) family in Tolypocladium guangdongense, Cordyceps militaris and Ophiocordyceps sinensis. Based on the structures of the C6 zinc domains, these proteins were observed to be evolutionarily conserved in ascomycete fungi. We focused on T. guangdongense, a medicinal fungus, and identified 139 C6 zinc genes which could be divided into three groups. Among them, 49.6% belonged to the fungal specific transcriptional factors, and 16% had a DUF3468 domain. Homologous and phylogenetic analysis indicated that 29 C6 zinc genes were possibly involved in the metabolic process, while five C6 zinc genes were supposed to be involved in asexual or sexual development. Gene expression analysis revealed that 54 C6 zinc genes were differentially expressed under light, including two genes that possibly influenced the development, and seven genes that possibly influenced the metabolic processes. This indicated that light may affect the development and metabolic processes, at least partially, through the regulation of C6 zinc genes in T. guangdongense. Our results provide comprehensive data for further analyzing the functions of the C6 zinc genes.